1. Field of the Invention
2. Description of Related Art
Most swimming pools have a weir in the form of a main chamber having an open top covered by a removable grid or lid (hereafter reference will only be made to the term "lid" for convenience), a suction port leading from the main chamber and being connected via suitable piping to a circulating pump and an inlet portal joining the main chamber to the pool, the level of the portal being such that, when the pool is filled with water, the level of the pool water is between the upper and lower extremities of the portal. Thus water is drawn into the chamber through the portal for circulation normally through, among other things, a filter and then returned to the pool at a position remote from the weirs. There are two main kinds of weir, viz a built-in weir and a molded plastic weir. In the latter case, the portal is in the form of a short tunnel. The water flow through the portal is normally controlled by a weir flap that is pivoted to the sides of the portal and that has the effect that the bulk of the water drawn into the chamber is the water at the surface of the pool.
Most modern pools are provided with automatic pool cleaners which are connected more or less permanently to the suction port through flexible piping, usually via a control valve which permits the ingress of water, so that water is drawn into the suction port through the weir as well as through the flexible piping. This piping normally enters the weir through the portal and thus inhibits the operation of the weir flap. Alternatively, the piping exits the chamber through the open top. While this permits the weir flap to operate, it is disadvantageous for a number of reasons, amongst which are that the piping will lie in the path of any person walking around the pool and that the lid must be removed so that the open top of the chamber will be unguarded.